I am still in my bed of pain, and you summoned me from the after-public-life of attempted recovery.
> I had no idea it was possible to use male-gendered terms in a generic way
This is just sarcastic, right? "Male gendering" is just a use, no gender is involved in plain terming (outside the obvious exception of intentional gendering)... "Wo-man" specifies "/sensitive/ man", but there is no gender in "man", in "having a mind"... "Human", i.e. "heartly", is not gendered - yet some languages typically correlate derivations like French "homme" with male in default understanding... This should be clear, but just to be sure.
> bro
To the best of my recollection, in the IE roots "brother" is "who assists in the rites" - not necessarily gendered. (Some add that the idea is "supporter".) The suggestion from the term is that of the "brotherhood" - which is not gendered (the idea of fraternity is not gendered). "Sister" should instead mean "welcome" (to some studies): not gendered in this case; others interpret it as gendered ("one's girl" - this is what Etymonline proposes).
> "Guys" I'll let pass no problem, maybe even "dude" too on a good day
That's odd. You wouldn't mind being called "a generic Italo- or possibly French ("Guido" or "Guy")"*; you wouldn't mind being called a "doodle", which has a connotation of "simpleton" - and you refuse "brother", which basically means to imply "getting close to you" (as an opening from the speaker)?
* Edit: Yes, also the explosion of the term and the non-national derivation from "Guy Fawkes" (from the celebration that involved displays of Guy Fawkes ragdolls) should be remembered. Still not precisely complimentary, I'd say.